Burr-minimal drilling without drill cap – where extensive deburring was previously required, the component now comes #burrfree straight out of the machine
Manufacturers are always looking for ways to make component production more efficient and cost-effective while maintaining or improving quality. However, no one would have expected that changing a drill at TRIES GmbH & Co. KG in Ehingen an der Donau would turn the entire production process upside down. After switching to the ExBurrDrill from deburring specialist KEMPF in Reichenbach-Fils, not only was the quality of the bores improved, but tool life was also increased tenfold, significantly reducing the effort required for deburring.
From the founding of the engineering office Manfred Tries in 1964, quality was the top priority, so it was not long before an in-house production was established and integrated alongside the development and design of hydraulic components. In 1978, the current TRIES GmbH & Co. KG was founded, which now employs nearly 180 people and is internationally known, among other things, for its hydraulic control blocks, valves, and cylinders. The focus then, as now, is on the development and design of custom solutions carried out in close collaboration with customers. Depending on the component and requirements, TRIES produces quantities ranging from a few single pieces to several tens of thousands per year, primarily used in specialty vehicles, wheeled excavators, and cranes from various major and well-known manufacturers.
High Effort for a Standard Component
In the production of a turned part with cross-holes for hydraulic blocks, measuring only about 120 mm in length and already a standard product at TRIES with an annual volume of approximately 25,000 pieces, the seemingly “simple” drilling operation proved to be a real bottleneck in the entire machining process. The drills used generated burr formation at the bore exit on the inside of the component that was sometimes so severe it required manual deburring in a first step, followed by thermal deburring by an external service provider in a second step. Additionally, the drills had a relatively short tool life, resulting in a lack of process reliability and unpredictability, as burr formation had to be repeatedly checked and drills had to be replaced after varying usage times (usually after about 2,000 bores). Overall, the production process was unsatisfactory for Robert König, the series production department manager, prompting the search for a new and improved solution.
The steel hydraulic housing clamped in the CNC machine. The applied ExBurrDrill with TiAlN coating (diameter 5 mm, Z=3) drills the four bores in the component within seconds, without requiring any subsequent deburring. This way, the workpiece comes out finished and already #burrfree straight out of the machine.
A Small Drill Delivers a Big Impact
After several attempts with various drills from well-known manufacturers, none of which achieved a satisfactory result regarding burr height at the bore exit, TRIES eventually turned its attention to the ExBurrDrill from KEMPF. The burr-minimized drill, developed by the deburring specialist, also promises that no drill caps remain on the component thanks to its special geometry. With the support of KEMPF field representative Thomas Welte, the drill was promptly tested at TRIES.
The component on the right and the cut-open version for inspection on the left. The complete bore is clearly visible, as well as the two cut bores on the left and right (in the left component). The bore diameter is 5 mm, and the inner diameter of the main bore at this point is 14 mm.
Although TRIES’ expectations were not very high due to numerous preliminary tests and a satisfactory performance would have already been achieved by eliminating external thermal deburring, the performance of the ExBurrDrill was all the more surprising. After being run in on several machines, burr formation at the bore exit was not visible or barely measurable even after producing many thousands of bores. In continuous operation since then, the performance has been so reliable that no inspection effort is required in principle, and the drill is proactively replaced after approximately 20,000 parts to prevent any potential burr formation.
The bore exit on the inside of the workpiece, shown in close-up, was produced after approximately 4,000 holes using the ExBurrDrill. There is no visible burr formation.
Performance Increase and Production Optimization
Since the introduction of the KEMPF ExBurrDrills, bore exits no longer require rework. The constant inspection effort and machine downtime associated with tool changes are also a thing of the past.
Robert König, head of serial production, is enthusiastic: “After the first successful use of the ExBurrDrill, the drill is now also used on other components in a total of three different diameters. The drill performs up to eight bores per component, and even in these applications, we no longer experience any issues with burr formation.”
The Project Team
Left: Thomas Welte, Technical Field Service Specialist at deburring expert KEMPF GmbH, and right: Robert König, Head of Series Production at TRIES GmbH & Co. KG, in front of the machine where approximately 25,000 workpieces are produced annually using the ExBurrDrill.
Designed for Minimal Burr at Maximum Feed Rate
The KEMPF ExBurrDrill offers additional advantages that can optimize machining compared to the use of standard drills in many areas. To fully leverage its benefits, the special drill from KEMPF is not offered as an off-the-shelf tool but is custom-made for the specific customer application in diameters ranging from 0.8 mm to 20 mm. Taking into account the engagement conditions at the bore exit and the workpiece material, the tool geometry of the ExBurrDrill is parametrically designed.
Custom tooling allows multiple process steps to be combined in a single drilling operation. For example, using a step drill can eliminate both the subsequent deburring process and a countersinking or reaming operation. This reduces tool change times as well as machining time on the machine.
In principle, the KEMPF ExBurrDrill was designed to perform burr-minimized drilling at ideally higher feed rates than standard drills, while also avoiding drill caps that always pose a risk to subsequent tools. Due to the special cutting edge of the ExBurrDrill, this risk is eliminated. If edge breaking on the workpiece is required, the subsequent deburring tool is significantly relieved by the minimal residual burr. If the bore is ECM-deburred, this process also runs with considerably fewer disruptions because the residual burr is much smaller.